The Kubuntu Backports PPA contains backports of new versions of KDE Platform, Plasma and Applications as well as major KDE apps for Kubuntu.

And now you can install Plasma 5.17.5 in Kubuntu 19.10 via the PPA by doing following steps one by one.

1.) Open terminal either from the application launcher or by pressing Ctrl+Alt+T on keyboard. When terminal opens, run command:

sudo add-apt-repository ppa:kubuntu-ppa/backports

Type user password when it asks, no asterisk feedback, and hit Enter to continue adding the PPA.

2.) After adding the PPA, run command to upgrade your KUbuntu desktop to get the latest packages:

sudo apt update && sudo apt full-upgrade

For non-KUbuntu users who want to install the KDE Plasma desktop, run command:

sudo apt install kubuntu-desktop

Note the command will install full Kubuntu desktop which may changes the login screen, startup splash, etc. Take a screenshot of the installed packages in terminal in case you want to restore your desktop.

Uninstall:

For any reason you can downgrade to Plasma 5.16.5 by purging the PPA via command: